From Nature, compelling evidence that climate change is making its impact well and truly felt. Firstly, this graph showing the trend for areas burnt by wildfires since 1984:
And while climate change alone cannot be blamed, it is not helping:
Across the American west, the area burned each year has increased significantly over the past several decades (see ‘Bigger blazes’), a trend that scientists attribute both to warming and drying and to a century of wildfire suppression and other human activities. Allen suggests that the intertwined forces of fire and climate change will take ecosystems into new territory, not only in the American west but also elsewhere around the world. In the Jemez, for example, it could transform much of the ponderosa pine (Pinus ponderosa) forest into shrub land. “We’re losing forests as we’ve known them for a very long time,” says Allen. “We’re on a different trajectory, and we’re not yet sure where we’re going.”
A combination of poor policy, drought and parasitic beetles aren’t helping:
Over the past century, however, the policy of quickly dousing fires has allowed brush and spindly young trees to build up in many western forests, so they tend to burn hotter and less patchily than before. And over the past decade, a severe drought across the southwest has weakened trees and made them vulnerable to widespread attack by beetles, leading to a die-off of more than one million hectares of piñon pines (Pinus edulis)1. Many of the dead trees are still standing, and can serve as ladder fuels that transform relatively cool surface fires into hot, fast-moving crown fires that leap from treetop to treetop.
Can the forests be saved? Perhaps – but they will never be as they were:
Given the uncertainties in how climate change, insect outbreaks and other stresses will affect forests in coming decades, Allen thinks that it is necessary to hedge bets after a fire by planting a range of species. He suggests building a “bridge to the future”, by mixing some of the original tree types with species from lower elevations or warmer slopes, which could do well as conditions change.
That approach would help to make the ecosystems more resilient. But it will not restore the past, says Allen, who is saddened by the dramatic changes in the Jemez Mountains and beyond. At the end of a long, dry and fiercely hot hike through the Las Conchas burn, he surveys the bare hillsides and recalls what they were like just over a year ago — forested, cool and full of life. “For so many of us who have worked here for so long,” he says, “this feels like a failure.”